ELLICOTT CITY, Md. (WUSA) -- Officials say that two people killed just before midnight in a train derailment in Ellicott City were two 19 year old women. They have been identified as Elizabeth C. Nass and Rose Louise Mayr.

Twenty two minutes before the derailment Nass tweeted: "Drinking on top of the Ellicott City sign with 2r0se_petals"

Nass was a student at James Madison University in Harrisonburg, Va. and a member of Alpha Sigma Alpha. University of Delaware officials confirm Mayr would have been a junior this year. Her major was nursing.

Howard County police released additional details about the accident on Tuesday afternoon. The teenagers' bodies were found, already deceased, seated on the edge of a bridge over Main St. Investigators believe the girls were sitting facing east toward Baltimore County, their backs to the side of the train as it passed a few feet away behind them.

When the train derailed for unknown reasons, the open cars filled with coal tipped over, spilling coal on Nass and Mayr, burying their bodies. Their causes of death are unknown pending autopsies.

Police investigators say there are Twitter photos believed to have been posted by one of the girls just before incident. This information will be verified after the girls' cell phones have been processed.

Maryland Gov. Martin O'Malley released a statement on Tuesday afternoon, which read: "It is tragic that we've lost two young women in the train derailment early this morning in Ellicott City. I've spoken with County Executive Ulman, and the State will continue to support our first responders and local partners in Howard County."

The NTSB has officially taken over the investigation and officials say that they will spend all day and possibly the night investigating the incident.

NTSB's Jim Southworth confirmed that 21 cars of the 80-car CSX train were all loaded with coal when they derailed just before midnight. The 3,000-foot-long, 9,000-ton train had two locomotives and was going 25 miles per hour at the time of the derailment, said Southworth. The two CSX employees on the train were uninjured. CSX officials say the train was traveling from Grafton, W.Va. to Baltimore.

Howard County Executive Ken Ulman on Tuesday morning said train cars fell off a bridge, approximately 17 to 20 feet, onto Main Street below. According to Ulman, the two killed in the derailment were likely walking along the Main Street/Frederick Road bridge which runs over the Patapsco River under the CSX tracks. Southworth could not confirm that information during a news conference later Tuesday morning.

Southworth said on Tuesday morning that the investigation is going to take much more time and that officials will "turn over every stone." Officials and specialists are looking closely at the operation of the train and speeds before the derailment. Southworth also revealed that the train had a camera at the front but he was unable to download the video to view it yet.

Southworth took a moment at the beginning of his statement on Tuesday to express condolences to the families of Nass and Mayr. He also expressed appreciation to Howard County government officials and crews.

Heavy cranes are being used to remove rail cars off of automobiles parked in a lot next to the rail bridge. Southworth says clearing the parking lot has taken some time.

The cleanup process doesn't stop with the metal wreckage or the train. Piles of coal were scattered across the crash scene, Ulman said. The Department of the Environment is assessing the damage caused by the train's contents. Crews are working to shovel coal out of the street, in an effort to clear paths through the debris.

Main Street in Ellicott City is closed between the Howard County/Baltimore County line and Ellicott Mills as a result of the incident.

The Maryland State Highway Adminstration and Howard County Highways have placed multiple sign boards alerting motorists to use alternate routes such as Route 40.